Coordination Compounds of Alkali and Rare Earth Metals Based on Centrosymmetric Chlorine-Substituted Bis-Mercaptooxazole. Synthesis, Structure, and Luminescence

New coordination polymers were synthesized. A ditopic centrosymmetric organic ligand containing oxazole heterocycles, 4,8-dichlorobenzo[1,2d:4,5d´]bis(oxazole)-2,6(3H,7H)-dithione (H2L), was prepared and structurally characterized. It was shown that deprotonated H2L forms non-luminescent binuclear molecular complexes Li2L(THF)6 (I) and Na2L(DME)4 (II) with alkali metals, while complexes of H2L with lanthanides are ionic compounds [Ln(DMSO)8][L]1.5 (Ln = Nd (III), Yb (IV)) exhibiting moderate metalcentered emission in the near-infrared (IR) range, despite the absence of coordination of the ligand L to lanthanide ions. The molecular structures of H2L·2DMSO and I–III were established by X-ray diffraction (CCDC no. 2320461 (H2L·2DMSO), 2320462 (I), 2320463 (II), 2320464 (III)).